A stunning and large example of an iridescent ammonite fossil of the species Caloceras johnstoni from North Somerset, UK.
The matrix measures 102 mm (4 inches) tall and the ammonite measures 88 mm (3.46 inches), which is large for this fossil type. The shell sits in the original limestone matrix in which it was found. The ammonite is well preserved and has been prepared out of the rock to reveal the shell. The shell displays some beautiful iridescence with flashes of red and copper that appear as the viewing angle changes. There are also some small bivalve shells that had encrusted the ammonite while it lay on the seafloor being being buried and foosilied. The matrix has a cut-flat base to allow it to stand freely for display.
These fossils are highly sought after and very hard to find. They are preserved in the same way as the famous Canadian "Ammolite" ammonites that are turned into valuable gemstones. The fossil weighs 155 grams.
Around 200 million years old (Hettangian, Early Jurassic), this fossil would make a wonderful addition to any collection.